sparklin



Jan. 31, 1956 c. H. SPARKLIN 2,733,000

CUTTER MECHANISM FOR A VACUUM CLEANER Filed Nov. 16, 1951 3 sheets sheetl 31. 195 c. H. SPARKLIN CUTTER MECHANISM FOR A VACUUM CLEANER 3Sheets-Sheet 2 Filed Nov. 16 1951 Jan. 31, 1956 c. H. SPARKLIN CUTTERMECHANISM FOR A VACUUM CLEANER 3 Sheets-Sheet 5 Filed NOV. 16, 1951United States Patent 2,733,000 CUTTER MECHANISM non A VACUUM CLEANERCharles H. Sparklin, Chicago, Ill., assignor to Birtman ElectricCompany, a corporation of Iliinois Application November 16, 1951, SerialNo. 256,701 2 Claims. Cl. 230-132 This invention relates to a vacuumcleaner having a motor operated fan therein and relates particularly toa cutter device for severing solid foreign material deposited inanexhaust portion of the cleaner.

Q Electrically operated vacuum cleaners ordinarily employ a centrifugalfan for drawing dirt-laden air through the nozzle of the cleaner andexhausting it intoa porous bag in which the dirt is separated from theair. In many cleaners of this type it has been found that paper, Stringand other foreign materials tend to gather on any memberthat is locatedadjacent the periphery of'the fan and in the exhaust passage and againstwhich the foreign matter is blown by the fan. This foreign matter,particularly paper, often assumes such a large bulk that it seriouslyinterferes with the operation of the cleaner. In order to overcome theabove described problems, I have' invented a vacuum cleaner cuttermechanism by means of which paper and. other foreign material is severedinto smaller pieces and blown out with the exhaust air into the bag withthe remainder of the dirt. The new vacuum cleaner is provided with acentrifugal fan having a rotatable impeller and an exhaust passage wayof helical shape from'the impeller. This passageway has its entrance orshallowest part adjacent to the impeller and its exit spaced from theimpeller and rearwardly of the entrance. I provide a fixed cutter .bladeat this entrance on which bulky foreign material such as paper isdeposited and a second cutter blade on the impeller for rotationtherewith for cooperation With'the V fixed blade to sever foreignmaterial deposited at the entrance. With this structure one portionofthe severed material passes directly rearwardly out the exit and anotherportion passes around the passageway to be again cut if it again becomescaught at the entrance. In the preferred construction the fixed bladeextends across the full width of the exhaust passageway in the regionadjacent to the impeller and the blades are cuived and sloped to providea scissors action.

The invention will be described as shown in the accompanying drawings.Of the drawings: Fig. 1 is a fragmentaryjlongitudinal vertical sectionthrough a vacuum cleaner embodying the invention; Fig. 2 is a frontelevation of the rotatable impeller and associated structure; Fig. 3 isa fragmentary enlarged section taken substantially along line'33 of Fig.2; Fig. 4 is a fragmentary enlarged elevational view showing therotatable cutter blade approaching the fixed cutter blade; Fig. 5 is asection taken substantially alongline 5-5 of Fig. 1; and Fig.6 is a rearelevational view of themotor casing and associated structure of thecleaner. ;In the embodiment shown in the accompanying draw.-' ings thevacuum cleaner is supportedon spaced wheels 11 and is adapted to bepropelled by means of a'h'andle 12. The cleaner includes a casing13.within an outer housing 14. The casing 13 is provided with aremovable front portion 13a having roughly the shape of atruncated2,733,000 Patented Jan. 31, 1956 cally. The front portion 13a has anenlarged circular opening 13b at the front or apex thereof.

Spaced inwardly from the front portion 13a and substantially parallelthereto over a portion of its surface is a second casing portion 15.Between the casing portions 13a and 15 there is located a centrifugalfan 16 of generally conical shape having a plurality of blades 17thereon. The blades are curved in the customary manner, as shown in Fig.2, and extend slightly less than the full distance between the frontcasing portion 13a and the second casing portion 15. The outer edge ofeach blade 17 is substantially horizontal, as shown in'Fig. l, and thebase of the conical fan 16 is curved rearwardly so that these horizontaledges are substantially tangential to this curved portion. I

The casing 13 rearwardly of the removable casing portion 13a is providedwith an exhaust passage 18 of generally helical shape. As is shown inFig. 5, this exhaust passage which is of expanding cross sectioncommunicates through almost 360 with the exhaust from the centrifugalimpeller or fan 16. The entrance to the v munication with a dust bag inthe usual manner.

It has been found in actual tests that the entrance 19 to the exhaustpassage operates as a barrier against which pieces of paper and otherforeign material tend to gather. If not removed, this paper and the likeaccumulates to such a large amount that it interferes With the efficientwire withthe base portion arranged substantiallyvertioperation of thecleaner. In order to remove this foreign material there is provided afixed cutter blade 22 attached as by screws 23 to the entrance 19 of theexhaust passage so that the cutting edge 22a extends beyond the casingat this entrance in position to have paper and other foreign materialdeposited thereon. This fixed blade has the cutting edge 22a concavewith the point of deepest curvature being adjacent to the impeller 16.

Cooperating with the fixed cutter blade 22 is a second cutter blade24fastened to the impeller 16 for rotation therewith. In order tobalance the impeller it is provided with a thickened portionsubstantially diametrically opposite the blade 24, as shown in Fig. 1,and this portion serves as a counterbalance. The second cutter blade is'provided with an inclined cutting edge adapted to cooperate with thecutting edge 22a of the fixed cutter blade 22 and sever paper and thelike deposited thereon. As can be seen from Fig. 4, the concave cutteredge 22a and the sloped cutting edge 24a cooperate to have a slicingaction or a scissors effect.

In providing the exhaust passage 18 with a cross sectional areaincreasingflin size from the entrance 199i the exhaust passage to theexit 21 thereof, the rear wall 13c forming the exhaust passage ishelically curved. Added cross sectional areas are also provided by positioning the inner casing wall 13d inwardly with respect to the outeredge 17a of the blades 17. This gives the elfect of immediatelyenlarging the exhaust passage from the impeller 16 and speeds the volumeflow of air.

In order to rotate the fan or impeller 16, this impeller is mounted ona-wshaft 25 which serves as'an extension ofthe. motor shaft 26.This-shaft ZS-extends through theopening 13b and is provided with aspindle 27 for driving a belt 28; This belt passes around the spindle 27and then around the hub of a brush 29 for rotating this, brush. t

In the ordinary cleaner of the general type shown in the drawings it hasbeen found that hair, stringand the like work their way in behind theimpeller 16 and become wrapped around the rotating shaft 25 or aroundthe inner surface of the hub of the impeller 16 through which the shaft.25 extends. In order to prevent this action there is provided a shield30 attached to the casing that forms a part of the exhaust passage withthis shield extending over the peripheral rim of the impeller 16 toprevent foreign material entering behind the impeller. This shield isadjacent to the periphery of the impeller and overlaps the peripheralarea of the impeller, as shown most clearly in Fig. 3. The shield isspaced from the peripheralrim a distance sufiicient to permit normalplay in the shaft 25 and thus the impeller 16. In the embodiment shownin the drawings the shield includes an annular planar portion 30aextending outwardly from the inner Wall 13d of the exhaust passage 18and a cylindrical portion 30b overlapping the peripheral area or rim ofthe impeller 16. In the embodiment shown the casing portion 15 that isbehind the impeller 16 is attached to the remainder of the casing inwhich the exhaust passage 18 is located by means of spaced bolts 31. Theplanar portion 3th: of the shield is clamped between the casing portion15 and the casing portion in which the exhaust passage 18 is formed. 7

In order to provide efficient ventilation of the motor 32, there isprovided a centrifugal ventilating fan 33 mounted on the motor shaft 26immediately behind the front shaft bearing '34. Air is directed into thecenter of this fan 33 by means of a baffle 35 located inwardly of thefan 33 and the wall 13d defining the exhaust air passage 18 from thenozzle of the cleaner. This baliie 35 has a substantially cylindricalportion 35a positioned inwardly of the wall 13d and a substantiallyannular planar portion 35b located at the inner end of the portion 35a.This planar portion 35b extends to the wall 13a to make an effectivesealing contact therewith. On the front edge of the cylindrical portion35a there is provided another planar portion 35c extending inwardly andlocated just rearwardly of the rear edges of the blades 33a of the fan33. This planar portion 350 is provided with an air inlet opening 35dconcentric with the fan 33. This circular opening 35d is located justoutwardly of the innermost edges 33b of the fan blades 33a. With thisconstruction, rotation of the fan 33 causes air to be drawn across themotor 32 and through the opening 35a in the other planar portion 350 andthen forced outwardly by the rotating blades 33a into the passage 36defined by the inner surface of'the wall 13d, the cylindrical portion35a and the first planar portion 35b.

In order to provide entrance and exhaust of the motor cooling air, theframe 37 containing the inotor 32 is provided on its rear surface withair entrance openings 37a, 37b, 37c, 37d, and 37e. When the fan 33 is inoperation, air is drawn through these openings 37a to 37c,

inclusive, where it flows across the motor 32 and through the shieldopening 35d into the center of the centrifugal fan 33. From this fan,the air flows outwardly between guide means formed by the second casingportion 15 and bafiie planar portion 350 and then through the passage36. The air then passes out an opening 38 (Fig. 5) to the atmosphere.This opening is formed by cutting away a portion of the casing 13d justto the rear and upwardly of the exhaust passage entrance 19. This cutoutpart forming the opening 38 extends arcuately around the fan 33 about 90(Fig. 5) and is located to the right of the casing forming the exhaustair passage when the cleaner is viewed from the front of Fig. l.

The bafiie 35 and associated structure have a multiple function. In onerespect, by locating the cylindrical 'por tion 35a adjacent themotor 32the shield serves to direct air across the motor for maximum cooling.Similarly, the inwardly directed planar portion 35c also aids indirecting air across the motor. The combination of the portion 35a andthe planar portions 35b and'35c also provide one side of the outletpassage 36 for exhausting the air from the centrifugal fan 33'. Bylocating the guide means including the planar portion 35c adjacent tothe blades 33a the fan 33 operates at maximum efiiciency to draw astrong air current across the motor in substantially streamline flow. Bylocating the inlet opening 35d in the bafiie adjacent the inner edges ofthe blades 33a, all of the air is directed to the inner edges of theblades 33a so that maximum suction and thus maximum air flow isobtained.

By locating the fixed cutter blade 22 at the entrance 19 to the exhaustpassageway 18 with the exit 21 of the passageway spaced from theimpeller 16 and rearwardly of the entrance 19 and by providing a secondcutter blade rotatable with the impeller and cooperating with the fixedblade to sever foreign material deposited at this entrance and thus onthe fixed blade, one portion of the severed material will pass directlyrearwardly and through the exit 21 into the dust bag of the cleaner. Theother portion which will be forwardly of the fixed blade 22 as seen inFig. 1 will pass around the exit passageway 18 so that it can again becut if necessary and if it again catches on the fixed blade 22. Thisarrangement and operation not only prevents jamming of the impeller butalso insures that all large particles are immediately cut into smallpieces and exhausted into the bag. This has the dual effect of providingthat all foreign matter be exhausted into the bag without delay and alsoresults in a smooth air fiow and less back pressure as any particlesflowing around the exhaust passageway with the air are necessarily smallcomminuted particles except possibly the foreign material which passdirectly rearwardly from the fixed blade 22 out the exhaust 21. Thislatter material is in the exhaust air stream such a very small time ithas little eifect on raising the back pressure.

The ventilating apparatus including the fan 33, baflle 35-and associatedstructure is described and claimed in Addison Ballard Bradley, Jr.application Serial No. 256,726, filed November 16, 1951. The threadshield including the member 30 and associated structure is described andclaimed in Frank S. Howard application Serial No. 256,874, filedNovember 17, 1951.

Having described my invention as related to the embodiment shown in theaccompanying drawings, it is my intention that the invention be notlimited by any of the details of description unless otherwise specifiedbut rather be construed broadly within its spirit and scope as set outin the accompanying claims.

Iclaim:

1. In a centrifugal fan structure including a rotatable fluid impellerand means constituting an exhaust passage extending around the impellerperiphery and rearwardly thereof in'an axial direction, the exhaustpassage increasing in depth helically substantially parallel to saidaxial direction from an area of substantial width adjacent to theperiphery to an exhaust port, a fixed cutter blade located at said areaand extending laterally across the exhaust passage to catch foreignmaterial that may be lodged at said area, and a second cutter blade onthe impeller for cooperation with the fixed blade to sever materiallodged thereon, both said cutter blades being located beyond theperiphery of the impeller to prevent substantial interference with theoperation of the impeller.

2. The fan structure of claim 1 wherein the fixed cutter blade isprovided with a concave cutting edge of relatively great depth and thesecond cutter blade is provided with a cutting edge sloped with respectto said concave cutting edge and cooperating with said concave cuttingedge to produce a scissors action therebetween.

References Cited in the file of this patent UNITED STATES PATENTS

